HDInsight Basics: Nodes

Abdullah Al Mahmood explains some of the basics of Azure HDInsight, including what Hadoop means by nodes:

HDInsight clusters consist of several virtual machines (nodes) serving different purposes. The most common architecture of an HDInsight cluster is – two head nodes, one or more worker nodes, and three zookeeper nodes.

Head nodes: Hadoop services are installed and run on head nodes. There are two head nodes to ensure high availability by allowing master services and components to continue to run on the secondary node in the event of a failure on the primary. Both head nodes are active and running within the cluster simultaneously. Some services, such as HDFS or YARN, are only ‘active’ on one head node at any given time (and ‘standby’ on the other head node). Other services such as HiveServer2 or Hive Metastore are active on both head nodes at the same time. There are services like Application Timeline Server (ATS) and Job History Server (JHS) which are installed on both head nodes but should run only on the head node where Ambari server is running. If these components sound unfamiliar, please revisit the article on Hadoop ecosystem in HDInsight.

Read on to see the other classes of nodes HDInsight uses.

Related Posts

CosmosDB Time To Live Support

Hasan Savran explains the Time To Live (TTL) counter in CosmosDB: Another great feature of Cosmos DB is, TTL (Time To Live) support. This is a great option to have if you need a database system with Caching option, or you need to purge your data and you don’t want to develop a function to […]

Read More

Testing Kafka Streams Applications

Yeva Byzek continues her series on testing Kafka-based streaming applications: When you create a stream processing application with Kafka’s Streams API, you create a Topologyeither using the StreamsBuilder DSL or the low-level Processor API. Normally, the topology runs with the KafkaStreams class, which connects to a Kafka cluster and begins processing when you call start(). For testing though, connecting to a running […]

Read More

Categories

March 2017
MTWTFSS
« Feb Apr »
 12345
6789101112
13141516171819
20212223242526
2728293031